With the rapid development of the global economy, steel structures have played a pivotal role in the field of construction, playing an increasingly important role. Whether in industrial or civil buildings, steel structures are rapidly occupying more and more with their outstanding characteristics Wide market. Its characteristics are: its overall rigidity and seismic performance are good, the construction speed is fast, the self-weight is low, and the bearing capacity is high. It replaces the reinforced concrete structure in large-span and super high-rise buildings, but it also has the disadvantages of poor fire performance and easy corrosion. In order to better play the role of the steel structure in the design according to its characteristics, it is better to play the role of the steel structure, and now the steel structure plant design status and optimization countermeasures are analyzed.
A. Overview of steel structure industrial plants
1 Advantages of steel structure industrial workshop
At present, in the process of engineering plant design and construction, people mainly use steel structure materials as their main construction materials, and their advantages are mainly reflected in the following aspects:
(1) In the process of on-site construction of industrial plants, steel structure materials can be mass-produced industrially, and the mechanical equipment used can be assembled on-site during the construction process. Therefore, this greatly shortens the construction period of the project and reduces the total project investment cost.
(2) Compared with steel structure materials and concrete structure materials, steel structure materials have the characteristics of lightweight and high strength. Therefore, in the practical application process, not only can the load generated by the building structure be greatly reduced in use It also effectively improves the stability and reliability of the plant structure. And after taking reliable anti-corrosion measures, the steel structure also has strong corrosion resistance when used, which also makes the industrial plant structure in use will not be affected by external environmental factors, making its structure stable and durable problem appear.
(3) The strength of the steel structure material is relatively high in the process of use, the investment cost is also relatively low, and it can also be recycled many times, which makes the steel structure industrial plant have good environmental protection and energy-saving function, which is suitable for China's social economy. Sustained development has laid a solid foundation.
2 Design principles of steel structure workshop
When designing a steel structure industrial plant, the materials, structural schemes, and construction measures should be selected reasonably according to the actual situation of the project to meet the requirements of strength, stability, and rigidity of structural members during transportation, installation, and use, and meet the requirements of fire prevention and corrosion prevention, And should prefer to use common and standardized components to reduce the production and installation workload. The steel structure design document shall indicate the design service life of the building structure, the steel grade used, and the model (or steel number) of the connection material.
B. Main features of the structural design of steel structure industrial workshop
Steel structure workshops are widely used all over the world, especially in developed countries. Steel structure workshops are usually suitable for storage warehouses, industrial workshops, exhibition halls, purification workshops, and supermarkets. The main features of their design are as follows:
① has a large space and span, and the construction quality is light and the strength is extremely high;
② The most advanced method is generally used in the design, which can fully meet the requirements of steel in impact resistance, deformability, seismic resistance, and rigidity;
③The steel structure can be used repeatedly, and it is very convenient to move and move, avoiding the waste of a large amount of steel, protection The environment is not polluted;
④ The steel structure is unique and lightweight, the actual occupied area is small, the application area is wide, and the used space in the building is increased;
⑤ The component parts are standard, well-made, easy and fast to install, effectively shorten the construction period and reduce investment Cost;
⑥ After taking reliable fire prevention and corrosion prevention measures, it has higher fire resistance and stronger corrosion resistance.
C. Design status and optimization measures of steel structure industrial workshop
In the study of the stability of steel structure workshops, the most important content is the coupling effect of axial force and bending moment, and then the overall stability. The relationship between overall and local stability. At present, the safety factor in the design of steel structure workshops cannot reflect the correlation between the whole and the part. The structural parameters are uncertain, the structural response is significantly different, and the random parameter structural extremum is in an unstable state. Therefore, it is necessary to continuously optimize the design of the steel structure plant to improve its performance and safety performance.
1 Optimize the thermal insulation and fire protection of steel
Steel has very high thermal conductivity, and its thermal conductivity is 50 w (m.℃). When heated to above 100 ℃, its tensile strength will decrease and plasticity will increase; when the temperature reaches 250 ℃, the tensile strength of steel It will increase slightly, but the plasticity will decrease, and the phenomenon of blue brittleness will appear; when the temperature reaches 500 ℃, the strength of the steel will drop to a very low level, which will cause the steel structure to collapse. Therefore, when the ambient temperature of the steel structure is above 150 ℃, heat insulation and fire protection design must be done. The general method is as follows: the outer side of the steel structure is covered with refractory brick, concrete or hard fireproof plate. Or steel structure brushed thick fireproof paint.
2 Optimize the facade design of the steel structure industrial plant
The construction of light steel structure mainly has the following four characteristics: scale, line, color, and change.
The facade of the steel structure industrial plant is mainly determined by the process layout. Under the requirements of the process, the facade is simple and magnificent while making the nodes as simple and unified as possible. The color profiled steel plate makes the construction of the light steel factory building appear light and colorful, which is obviously superior to the traditional heavy reinforced concrete structure. In the design of light steel workshops, jumping colors and cool colors are often used, with emphasis on the main entrances, outer gutters, and flooding at the edges, which not only embodies the magnificence of modern factories but also enriches the facade effect.
In traditional industrial buildings with reinforced concrete structure, the exterior wall is maintained as brickwork, and the exterior decoration is made of paint or face brick, supplemented by color ribbons. Due to the unsatisfactory effect of the lighting windows on the concrete roof, a large number of lighting windows are usually installed on the wall during design. However, this is not the case for steel structure workshops whose maintenance walls are colored profiled steel plates. Lines are the most unique characteristics of light steel structure architectural style. The uniform lines are horizontal or vertical, making the light steel structure building full of smooth metal texture, reflecting a strong modern industrial atmosphere.
3 Optimized steel structure industrial plant support system
In the layout process of the column support system and roof support system of the steel structure industrial plant, it should be determined according to the actual vibration equipment, tonnage, span, structural form, column network setting, height, and crane setting of the plant. Generally speaking, the purlins of the roof structure are not considered, and are mainly set on vertical supports. In purlin-free systems, the roof slab is welded to the roof truss to achieve the purpose of winding support. But in the actual design process, due to the constraints of construction conditions. In consideration of the installation requirements, the winding lateral support system should be set at the winding position of the roof frame and the winding position of the skylight frame. At the same time, when the space between the factory buildings is above 12m, or when extra heavy vibration equipment and bridge cranes are installed, a longitudinal horizontal support system should be set.
4 Optimize the roof design of the steel structure industrial plant
In the roof design of the steel structure factory building, the main content is waterproof. Roof waterproof design mainly considers three factors: one is the roof slope; the other is the gutter form; the third is the length of the single-slope roof. The relevant roofing engineering technical standards are implemented. In actual engineering, the slope of many factory buildings is between (2% and 3%), which meets the actual requirements. Considering factors such as material performance, node processing and technology, the slope should be set to 5%. In the snow-covered area, the slope should be increased, and the single-slope roof length design of the steel structure factory should pay attention to the temperature difference and rainfall changes in the area. According to the relevant engineering design data, the length of the single-slope roof must be controlled below 70m to ensure the performance of the plant. When this standard value is exceeded, special treatment is required. At present, there are two main design schemes for steel structure roofs that are widely used: first, double-layer color profiled steel plates are used, and their thermal insulation cotton helps waterproof, but the temperature changes are large, and it is difficult to solve the problem of thermal expansion and contraction; second It adopts a composite flexible steel roofing system composed of the thermal insulation layer, steam barrier layer, coiled material waterproof layer, etc., covered with flexible coiled material, which helps to improve the condition of thermal expansion and contraction.
5 Anti-rust treatment
The steel structure surface will be corroded when directly exposed to the atmosphere. When there is an aggressive medium in the air of the steel structure workshop or the steel structure is in a humid environment, the corrosion of the steel structure workshop will be more obvious and serious. The corrosion of the steel structure will not only reduce the cross-section of the component but also cause local rust pits on the surface of the steel component. When the component is stressed, it will cause stress concentration and premature failure of the structure. Therefore, sufficient attention should be paid to the anti-corrosion problem of steel structure factory building components, and corresponding countermeasures and measures should be taken in terms of the general layout, process layout, material selection, etc. according to the erosion medium conditions and environmental conditions of the factory building to ensure the structure of the factory building. Safety. The anticorrosion of the general steel structure often uses anti-rust primer and topcoat, and the number and thickness of the coating layer are often determined according to its use environment and coating properties. Generally, the indoor steel structure is required to have a coating thickness of 100 μm under the action of natural atmospheric media, that is, two primers and two topcoats.
It can be seen that in the process of designing the steel structure industrial plant, we not only have to make strict requirements on the strength, stability, seismic performance, durability and other aspects of the steel structure plant, but also focus on taking reliable fire prevention and corrosion prevention measures. In order to effectively improve the stability and reliability of the industrial plant structure.